SU939977A2 - Device for measuring power on electrical machine shaft - Google Patents

Description

(54) DEVICE FOR MEASURING POWER ON THE SHAFT OF ELECTRIC MACHINE

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The invention relates to a measurement technique, in particular, to means for measuring the power expended by an electric motor in the study of heat and mass transfer in apparatus with baffles and other similar cases to.

On the main auth, sv. No. 761857. A device is known for measuring power on the shaft of an electric machine l.

The drawback of the device is the mala, Q la accuracy of measurement at low rotational frequencies due to the instability of the torque, due to the nature of the dry friction in contacting pairs .15

The purpose of the invention is to show the measurement accuracy at low rotational frequencies.

The goal is achieved by introducing into the device a motor control system, a contact calla, an electric motor with two brushes mounted on the shaft and a resistance meter

on brushes whose output is connected to the motor control system.

The drawing shows a diagram of the proposed device.

The device also contains a control system 1 to which the electric motor 2 is connected, on the same shaft with which the meter 3 is installed rotation speed and the slip ring 4 with brushes, the resistance of which is measured by the meter 5 resistance.

The device also contains the recorder 6, the multiplication unit 7., the load current sensor 8, the rotation frequency setting unit 9.

The device works as follows.

Claims (1)

The engine receives power from block 1 and develops a certain speed. The control system is closed in speed, so when measured under load, the speed does not change significantly. Information about the speed is given by block 3, about the moment - by block 8. The multiplication of ethyl signals gx-ussh: tvtgg by block 7, which is proportional to power: on the motor shaft. The system works satisfactorily at speeds higher than 30% (; | b / min. Lower frequencies of rotation are maintained less accurately, in particular, in the ETO-1 electric drive with a power of 245 W, the error is 4-5%. This happens Dry friction, which are non-linear in nature. To compensate for this change, a rotating ring 4 was used, which was in contact with two brushes, the resistance of which was measured by block 5. Three low frequency of rotation, the shaft was moving: not continuous, but in jerks. moving contact in The principle is similar to the nature of the moment of dragging dry friction forces. Therefore, during a pause, when the moment is greatest, the contact resistance will be the smallest, and when it moves, the moment will drastically decrease, the resistance will sharply increase. so that with an increase in the moment when there is a tendency for a drop in speed, the control signal increases, in the same way, a control circuit with respect to the moment of dry friction force is introduced into the device. The introduction of the control loop almost completely compensates for the dry friction forces, more accurately stabilizes the rotation frequency, which improves the overall measurement accuracy. The invention The device for measuring power on the shaft of an electric machine according to the author. St. NO 761-857, characterized in that, in order to control the measurement accuracy, an engine control system, a contact ring mounted on the electric motor shaft, with two brushes, and a resistance meter on the brushes, the output of which is connected to the electrical control system, are entered into it. rodvigatelem. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 76185,7, cl. G01 L 3/10, 31.O7.78.